Automatic cycling discharging device

ABSTRACT

The device has a timing system which consists of two chambers interconnected by a constricted passage and by a quick opening valve one chamber being permanently filled with a timing fluid, advantageously a liquid. A flexible member having means providing snap action forms the wall between one of these chambers and a discharge chamber from which pressure fluid is ejected to the atmosphere. Pressurized fluid from a pressure pack, such as an aerosol container, passes first to a metering chamber and then to the surface of the flexible member by which it is ejected through a discharge outlet.

United States Patent Freeman et al.

AUTOMATIC CYCLING DISCHARGING DEVICE lnventors: John D. Freeman, Westport; David E.

Earls, Norwalk, both of Conn.

Assignee: General Time Corporation, Phoenix, Ariz.

Filed: Oct. 29, 1970 Appl. No.: 84,961

U.S. Cl ..222/70, 137/624. 14, 222/335, 222/499 Int. Cl ..B67d 5/08 Field of Search ..222/16, 22, 59, 61, 70, 72, 222/335, 402.2, 494, 499, 54, 71, 397; 137/624.14;

References Cited UNITED STATES PATENTS 11/1969 Magel ..222/70 1 mi SMIIIIIIZIII/ll/ A m 3,497,108 2/1970 Mason ..222/70 X Primary ExaminerSamuel F. Coleman Assistant Examiner--Larry Martin AttorneyPennie, Edmonds, Morton, Taylor & Adams 5 7] ABSTRACT The device has a timing system which consists of two chambers interconnected by a constricted passage and by a quick opening valve one chamber being pennanently filled with a timing fluid, advantageously a liquid. A flexible member having means providing snap action forms the wall between one of these chambers and a discharge chamber from which pressure fluid is ejected to the atmosphere. Pressurized fluid from a pressure pack, such as an aerosol container, passes first to a metering chamber and then to the surface of the flexible member by which it is ejected through a discharge outlet.

8 Claims, 8 Drawing Figures PATENTEBAPR 2 5 I972 SHEET 1 0F 3 INVENTORS JOHN D. FREEMAN BY DAVlD E. EARLS ATTORNEYS SHEET 2 BF 3 INVENTORS JOHN D. FREEMAN BY DAVID E. EARLS ATTORNEYS PATENTEDA RZ' I912 3,658,209

- SHEET 3 UP 3 Port 3| 0nd V-2 Open Valve 9 0nd V-1 Open Snap-Over Point FIG. 5

Deflection Port 30 0nd V-3 Close Pressure INVENTORS JOHN D. FREEMAN DAVID E. EARLS ATTORNEYS rllllll/ BACKGROUND OF THE INVENTION Such devices are known in the art which functionto eject metered quantities of the-contents of the pressure pack at-certain time intervals. A serious disadvantage of these prior devices is their relatively high cost inasmuch as they employ as the timing mechanism electrically powered or spring powered clockwork units, or mechanical devices operated by the pressurized fluid which are highly complicated in their construction and operation.

SUMMARY OF THE INVENTION The invention relates to the automatic release .at predetermined time intervals of pressurized fluid from containers, aerosol containers being one example. The device is "entirely self-contained and requires no'external mechanism for controlling the periodic discharge.

The automatic cycling device includes two systems or sections, a timing system and a pressurized fluid system or section. The timing system features two chambers one of which is permanently filled with a timing fluid. These chambers are interconnected by a constricted passage and by a quick acting pressure equalizing valve, and the inner wall of one of the chambers may be formed by a flexible diaphragm, advantageously a snap action diaphragm. However, any diaphragm or flexible member having associated therewith some means for biasing it from its central position towards its opposite end positions may be used.

The pressurized fluid section includes a control and discharge chamber one wall of which is formed by this diaphragm or flexible member. This section includes also a metering chamber into which the pressurized fluid from the pressure pack flows at predetermined times. There is a passage between these two chambers and a valve stem fixed to the diaphragm extends through this passage and the metering chamber. In one form of the invention the portion of the valve stem between these two chambers has an internal duct provided with valve ports which cooperate with stationary sealing rings location respectively adjacent the bottom wall of the control or discharge chamber and adjacent the top of the metering chamber. A shoulder at the lower end of the valve stem cooperates with a third sealing ring at the entrance to the metering chamber to control the admission of pressurized fluid from the pressure pack.

In a second form of the invention an inlet from the pressure pack extends alongside of the valve stem, which is fixed to the diaphragm as in the first form of the invention. This inlet passage conducts the pressure fluid to the diaphragm and metering chamber or area. The valve stem controls both an admission valve in the inlet passage and a discharge valve by which the pressure fluid is admitted to the discharge inlet. The timing system is the same two-chamber system as in the first form of the invention.

The cycle of operation starts with the metering chamber or area filled and with the valve stem in its outermost position. The pressure fluid flows inwardly to the diaphragm and forces the diaphragm inwardly thus causing the timing liquid to flow through the restriction passage intothe other of the two chambers. When the diaphragm reaches its snap action-or snapover position its inward movement is accelerated and the diaphragm contacts and opens the quick acting valve thus quickly equalizing the pressure in the two chambers. The control or discharge chamber is connected with a discharge outlet through which the metered amount of pressurized liquid is ejected into the atmosphere. As the pressure in the control chamber drops the diaphragm supplies an outward force returning the valve stem to its initial position. A new cycle begins immediately. I

BRIEF DESCRIPTIONOF THE DRAWINGS FIG. 1 is a perspective view on a greatly reduced scale showing the automatic spray device of the invention and the upper portion of an aerosol can;

FIG. 2 is a view in vertical central section of the spray device drawn to a greatly enlarged scale;

FIGS. 2a and 2b are somewhat diagrammatic vertical sections of a priming and shut-off valve;

FIG. 3 is a view similar to FIG. 2 but with the diaphragm and valve stem assembly in a different position;

FIG. 4 is a third view similar to FIG. 2 with the diaphragm and valve stem assembly in still another position;

FIG. 5 is a pressure-deflection curve of the snap action diaphragm, and

FIG. 6 is a vertical central section similar to FIGS. 2, 3 and 4 showing a modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1-4 the automatic cycling dischargingdevice of the invention has a body member 1 and will be described as in vertical position and secured to the top of an aerosol container 2 (FIG. 1). Body 1 contains an upper timing chamber 3 and a lower timing chamber 4 separated by a horizontal partition 5. Upper chamber 3 is shown closed by means of a cover 6 although it may be closed in any other desired manner. But if desired upper chamber 3 may be open to the atmosphere. Lower chamber 4 is defined between partition 5 and the upper surface of a flexible snap action diaphragm 7, the peripheral edge of which is mounted in fixed position in any suitable manner in the vertical wall of body 1. For this purpose body 1 may be made in two parts, if desired.

The timing chambers 3 and 4 are interconnected by means of a constriction passage 8 and by a large valve opening 9 through partition 5. As shown, constriction passage 8 is formed in a nose piece 10 projecting from one side of body 1 and may include a tortuous portion 11. The degree of constriction will depend upon the frequency of ejection of the pressurized fluid desired. The frequency of ejection may be made variable if desired by making passage 8 adjustable to vary the amount of constriction. Valve opening 9 is closed by means of a pad 12 fixed to the end of a valve member 13 which is pivoted at 14 to the underside of partition 5. A light fiat spring 15, also mounted beneath partition 5, biases valve member 12 to closed position.

When the device is not in operation lower chamber 4 and at least the lower portion of constriction passage 8 are filled with a timing liquid and chamber 3'may be partially filled. A closed timing system for the automatic cycling device is thus provided.

Cooperating with this closed timing system is the pressure fluid section of the device which will now be described. This section includes a control and discharge chamber 16 formed between the lower side of diaphragm member 7 and the floor 17 of the cylindrical cavity for the diaphragm within body member 1, together with a metering chamber 18 and a fluid passage 19 which extends between these two chambers 16 and 18. Completing the pressurized fluid section is a valve means activated by diaphragm 7 which as shown includes a valve stem 20 which is fixed to the central portion of diaphragm 7 and extends downwardly through passage 19 and through metering chamber 18 to and slightly beyond the bottom thereof.

Metering chamber 18 is formed in the upper portion of a cylindrical member 21 the upper end of which is received in a threaded opening in body 1 as shown and which at its lower end is joined in any suitable manner to the upper end of the siphon tube 23 of the aerosol container. Member 21 includes a manual priming and shut-off valve 22 to be described.

The discharge outlet for the pressurized fluid is shown at 24 and includes a channel 25 leading from passage 19. Passage l9 surrounds the upper portion of valve stem 20, and the valve stem is hollow at its upper portion forming a duct 33 which is somewhat longer than passage 19.

The lower end of valve stem 20 is slabbed to provide a shoulder 26 which cooperates with a sealing ring 27 in order to control the admission of pressure fluid from siphon tube 23 to metering chamber 18. At the upper end of metering chamber 18 there is a second sealing ring 28, and just below the surface of floor 17 of control chamber 16 there is a third sealing ring 29. Valve ports 30 and 31 opening laterally into duct 33 in hollow valve stem 20 cooperate respectively with sealing rings 28 and 29 to control the flow of the fluid to the discharge chamber 16 and from this chamber, through passage 19 to the outlet channel 25. As shown an upstanding projection 32 above diaphragm 7 actuates valve member 13.

In order for the device to function metering or receiving chamber 18 must be primed first, i.e., filled with pressure fluid from the aerorol container. This is accomplished by manually turning the priming and shut-off valve 22 to the position shown in FIG. 2a where the pressure fluid from siphon tube 23 can flow through the curved passage 22a in valve member 22 to a passage 22!; which conveys the fluid to metering chamber 18 independently of the valve formed by the shoulder 26 and sealing ring 27. When valve 22 has been in the position of FIG. 20 for a sufficient time for chamber 18 to be filled, which requires only a matter of seconds, valve 22 is manually turned to the operating position shown in FIG. 2. When it is desired to discontinue the operation of the cycling discharging device valve 22 is manually turned to the position shown in FIG. 2b.

In the operation of the device, assuming that pressurized liquid has been admitted to fill metering and receiving chamber 18, and with ports 30 and 31 in the position of FIG. 2 this metered volume of liquid can flow through port 30 into duct 33 in valve stem 20 and thence upwardly and through port 31 into discharge chamber 16.

It will be understood that the pressurized fluid from the pressure pack or aerosol can 2 includes a propellant and an active ingredient. The character of the latter will depend upon the type of discharge desired, whether an insecticide, room freshener, or other.

The aerosol or other pressurized liquid may vaporize partially in order to fill control and discharge chamber 16 whose volume may be greater than that ofmetering chamber 18.

The pressure within control or discharge chamber 16 exerts an upward force on diaphragm 7 (FIG. 2) and the timing liquid filling chamber 4 begins to flow through constriction 8 into chamber 3. The diaphragm moves upwardly at a rate determined by the pressure exerted by the pressurized fluid against diaphragm 7 and the resistance to flow provided by constriction 8. After a predetermined time the diaphragm and valve stem assembly will have moved up to the position shown in FIG. 3 where port 30 is closed by sealing ring 28 and projection 32 is in contact with valve lever 13. Soon after this diaphragm 7 passes the knee of its force-deflection curve (FIG. and is at its snap action or snap-over point. It continues to move up under its reversed deflecting force and still under the fluid pressure in control chamber 16. This movement raises the right end of valve lever 13 and thereby opens valve port 9 slightly as shown in FIG. 3.

When valve port 9 starts to open timing liquid in chamber 4 begins to pass at a faster rate into chamber 3. The diaphragm and valve stem assembly can then move upward at a faster rate opening valve port 9 wider. This valve arrangement provides an avalanche action dumping liquid from chamber 4 into chamber 3 so that the diaphragm valve stem assembly moves up quickly to the position shown in FIG. 4. Pressurized fluid from control chamber 16 now passes through port 31, duct 33 and port 30 into annular passage 19 and into outlet channel 25 and thence into the atmosphere through discharge outlet 24. In the upper position of valve stem 20 shoulder 26 is raised above sealing ring 27 thus permitting another metered volume of pressurized liquid to refill receiving and metering chamber 18.

Pressure in discharge chamber 16 is maintained so long as liquid propellant exists therein. After all liquid is expelled or vaporized the pressure will quickly drop and diaphragm 7 will begin to move downwardly. In so doing the diaphragm will pass its snap action or snap-over point and will therefore supply a downward force to drive valve stem 20 to its lowest position. During this time the timing liquid from upper chamber 3 returns to lower chamber 4 through valve port 9, valve 12 opening against the flexing of spring 15 due to the decreased pressure in chamber 4. Some of this liquid also returns through constriction passage 8. The mechanism is now ready to repeat the cycle described above, the parts having returned to their positions as shown in FIG. 2.

In a second form of the invention shown in FIG. 6 an inlet from the pressure pack extends alongside the valve stem and conducts the pressure fluid to the metering chamber and diaphragm. No priming valve is required. The device has a body 34 having upper and lower timing chambers 35 and 36 separated by a horizontal partition 37. A cap member 38 closes the top of chamber 35.

A snap action diaphragm 39 is mounted with its circular rim in fluid-tight relation around the lower corner of lower chamber 36. A timing liquid fills chamber 36 and may be introduced through the opening 40 closed by a screw threaded plug.

Chambers 35 and 36 are interconnected by means ofa constriction passage 41 and a quick opening valve V-l which is mounted at the lower part of an upright threaded rod 42 and maintained in normally closed position by a helical spring 43. Valve V-l is actuated by a lever 44 centrally pivoted on the lower end of a screw-threaded pin 45 and operated by contact with a nut 46 on the upper end of a valve stem 47 which is clamped to diaphragm 39 between nut 46 and a second nut 48. The left end of lever 44 is forked and bears down on a cross pin 49 on the lower end of valve rod 42.

Immediately below diaphragm 39 there is a recess 50 formed in the lower surface of chamber 36. The chamber formed by this recess serves the purposes of the metering or receiving chamber and the control and discharge chamber. At its left side as shown in FIG. 6 is the discharge valve V-2 at the lower end of a short valve rod 51 which has an aperture 52 at its upper end to receive an actuating lever 53. This lever is a thin metallic bar having an enlarged central opening for valve stem 47 and a forked right end for a screw 54 which forms a pivot for lever 53. Valve stem 47 operates lever 53 through an enlargement 55 which is part of the valve stem and which has a rounded upper surface as shown to engage the lower surface of lever 53.

Discharge valve V-2 is arranged within a vertical circular opening 56 extending upwardly from the lower surface of body member 34. It cooperates with a seat 57 supported on the upper end of a threaded member 58 which is screwed into the lower portion of opening 56. A coil spring 59 holds valve member V-2 in normally closed position. A discharge nozzle 60 is threadedly engaged with the lower end of member 58.

The device is supported on the upper end portion of a siphon tube 61 of an aerosol container 62. No priming valve is required but siphon tube 61 is provided with a shut-off valve 63 which may be closed when the cycling discharge device is not in use. The upper end of siphon tube 61 is received within the lower portion of an axial passage 64 through a cylindrical threaded member 65 which is mounted in a threaded opening 66 at the bottom of body 34.

In the upper portion of member 65 there is a coil spring 67 at the upper end of which is a third or inlet valve member V-3 which cooperates with a seat 68. Inlet valve V-3 is actuated by the head of an adjustable screw 69 which extends downwardly from the lower end of valve stem 47. This valve controls a passage for the fluid from the pressure pack 62 through axial passage 64 and a passage 70 alongside of valve stem 47 to the chamber formed by recess 50 and diaphragm 39.

In operation the device of FIG. 6 differs from the device of FIGS. 2, 3 and 4 in several respects as will be easily understood. A major difference is that the pressure fluid from the aerosol container 62 passes directly upward through axial passage 64 and passage 70 directly to the metering chamber or area and into contact with the lower surface of diaphragm 39. The metering area is formed by recess 50 and the passages connecting it with discharge valve V-2 as well as a small annular space around the lower rim portion of diaphragm 39. These areas are open to the aerosol container 62 until valve stem 47 moves upwardly and closes valve V-3.

At the start of a cycle valves V-l and V-2 are closed and V-3 is open. As the pressure fluid acts on diaphragm 39 it flexes upwardly pulling stem 47 with it and causes valve V-3 to close as indicated in FIG. 5. This occurs before the diaphragm reaches its snap-over point. The diaphragm continues upwardly passing this point and the rate of upward travel depends upon the rate of flow of timing fluid through constriction passage 41. Valve V-l opens allowing diaphragm 39 and stem 47 to move up faster and quickly open discharge valve V-2. Pressure fluid within the metering area above referred to is discharged through nozzle 60 to the atmosphere. As the pressure fluid is discharged its pressure on the diaphragm is reduced and this permits the diaphragm to relax to its intial position. The next cycle then commences.

It will be understood that other devices may be used in place of a snap action diaphragm. Thus for example a diaphragm having a linear pressure-deflection curve may be used in connection with a toggle mechanism or in connection with two permanent magnets, one arranged to urge the diaphragm in one direction, and the other arranged to urge the diaphragm in the opposite direction. Furthermore a bellows, or a mere flexible sealing member, wall or partition may be used in combination with a toggle mechanism or two permanent magnets.

We claim:

1. In an automatic fluid discharging device for use with a pressure pack containing pressurized fluid which includes mechanism actuated by said pressure fluid for intermittently discharging a spray of fluid from said pressure pack and including a discharge chamber one wall of which is flexible for varying the enclosed volume, the improvement which comprises,

a cooperating fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, one wall of such chamber being common with said flexible wall, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions to actuate said pressure equalizing valve.

2. An automatic fluid discharging device according to claim 1 in which the second chamber of the timing system is filled with a liquid.

3. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid which comprises:

a. a fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, at least one wall of the second chamber being flexible for varying the enclosed volume, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions thereof, and

b. a pressurized fluid section including,

a metering chamber having a valved inlet from the pressure pack,

means for introducing fluid from the pressure pack by way of said metering chamber to the second surface of said flexible wall,

a valve stem actuated by said flexible wall, a discharge outlet, and

valve means associated with said stem including said valved inlet for controlling the flow of pressurized fluid so that when said flexible wall is flexed outwardly said valve means permits flow to the outer surface of the flexible wall, also when said flexible wall is in the snap action position said valve means prevents fluid flow between the pressure pack and metering chamber and, when said flexible wall reaches a position beyond the said snap action position said pressure equalizing valve is opened permitting rapid motion of said flexible wall to its inwardly flexed position and thereby permitting flow of the metered fluid through the discharge outlet thus reducing the pressure on the outer surface of said wall and allowing said wall to flex to its outward position.

4. An automatic fluid discharging device according to claim 3 in which the second chamber of the timing system is filled with a liquid.

5. An automatic fluid discharging device for use with a pressure packcontaining a pressurized fluid which comprises:

a. a fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, at least one wall of the second chamber being flexible for varying the enclosed volume, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions thereof, and

b. a pressurized fluid section including,

a metering chamber having a valved inlet from the pressure pack,

means for introducing fluid from the pressure pack through said metering chamber to a third (FIGS. 2, 3 and 4) chamber one wall of which is formed by the outer surface of said flexible wall,

a valve stem actuated by said flexible wall, a discharge outlet, and

valve means associated with said stem including said valved inlet for controlling the flow of pressurized fluid so that when said flexible wall is flexed outwardly said valve means permits flow to the outer surface of the flexible wall, also when said flexible wall is in the snap action position said valve means prevents fluid flow between the pressure pack and metering chamber and, when said flexible wall reaches a position beyond the said snap action position said pressure equalizing valve is opened permitting rapid motion of said flexible wall to its inwardly flexed position and thereby permitting flow of the metered fluid through the discharge outlet thus reducing the pressure on the outer surface of said wall and allowing said wall to flex to its outward posit1on.

6. An automatic fluid discharging device according to claim 5 in which the second chamber of the timing system is filled with a liquid.

7. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid and having a siphon tube, which device has a body member including,

outer and inner timing chambers separated by a crosswise partition, the inner chamber having a crosswise snap action diaphragm the inner surface of which forms one wall of a control chamber,

a constriction connection between said chambers,

a member projecting from said body for connection with said siphon tube and having a receiving chamber for pressurized liquid,

a passage in said body interconnecting said control and receiving chambers,

a hollow valve stem fixed to the diaphragm and extending through said passage and through said receiving chamber,

said interconnecting passage having an annular space surrounding the valve stem,

an outlet channel in the body member extending from said annular space,

seal ring members surrounding the hollow valve stem and positioned respectively adjacent the outer surface of the control chamber, at the inner end of the receiving chamber and at the outer end thereof,

the hollow valve stem having lateral valve ports cooperating respectively with the control chamber seal ring and the seal ring at the inner end of the receiving chamber, and having a shoulder adjacent its inner end cooperating with the seal ring at the outer end of the receiving chamber,

a valve opening in said partition between said outer and inner timing chambers,

a spring closed valve cooperating with said opening, and

the diaphragm actuating said valve member to open the same on the diaphragm outer stroke thus quickly equalizing the pressure in the two timing chambers and allowing the diaphragm to complete its outward stroke and then commence its return stroke.

8. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid which comprises:

a, a fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, at least one wall of the second chamber being flexible for varying the enclosed volume, and means 

1. In an automatic fluid discharging device for use with a pressure pack containing pressurized fluid which includes mechanism actuated by said pressure fluid for intermittently discharging a spray of fluid from said pressure pack and including a discharge chamber one wall of which is flexible for varying the enclosed volume, the improvement which comprises, a cooperating fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, one wall of such chamber being common with said flexible wall, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions to actuate said pressure equalizing valve.
 2. An automatic fluid discharging devicE according to claim 1 in which the second chamber of the timing system is filled with a liquid.
 3. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid which comprises: a. a fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, at least one wall of the second chamber being flexible for varying the enclosed volume, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions thereof, and b. a pressurized fluid section including, a metering chamber having a valved inlet from the pressure pack, means for introducing fluid from the pressure pack by way of said metering chamber to the second surface of said flexible wall, a valve stem actuated by said flexible wall, a discharge outlet, and valve means associated with said stem including said valved inlet for controlling the flow of pressurized fluid so that when said flexible wall is flexed outwardly said valve means permits flow to the outer surface of the flexible wall, also when said flexible wall is in the snap action position said valve means prevents fluid flow between the pressure pack and metering chamber and, when said flexible wall reaches a position beyond the said snap action position said pressure equalizing valve is opened permitting rapid motion of said flexible wall to its inwardly flexed position and thereby permitting flow of the metered fluid through the discharge outlet thus reducing the pressure on the outer surface of said wall and allowing said wall to flex to its outward position.
 4. An automatic fluid discharging device according to claim 3 in which the second chamber of the timing system is filled with a liquid.
 5. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid which comprises: a. a fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, at least one wall of the second chamber being flexible for varying the enclosed volume, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions thereof, and b. a pressurized fluid section including, a metering chamber having a valved inlet from the pressure pack, means for introducing fluid from the pressure pack through said metering chamber to a third (FIGS. 2, 3 and 4) chamber one wall of which is formed by the outer surface of said flexible wall, a valve stem actuated by said flexible wall, a discharge outlet, and valve means associated with said stem including said valved inlet for controlling the flow of pressurized fluid so that when said flexible wall is flexed outwardly said valve means permits flow to the outer surface of the flexible wall, also when said flexible wall is in the snap action position said valve means prevents fluid flow between the pressure pack and metering chamber and, when said flexible wall reaches a position beyond the said snap action position said pressure equalizing valve is opened permitting rapid motion of said flexible wall to its inwardly flexed position and thereby permitting flow of the metered fluid through the discharge outlet thus reducing the pressure on the outer surface of said wall and allowing said wall to flex to its outward position.
 6. An automatic fluid discharging device according to claim 5 in which the second chamber of the timing system is filled with a liquid.
 7. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid and having a siphon tube, which device has a body member including, outer and inner timing chambers separated by a crosswise partition, the inner chamber having a crosswise snap action diaphragm the inner surface of which forms one wall of a control chambEr, a constriction connection between said chambers, a member projecting from said body for connection with said siphon tube and having a receiving chamber for pressurized liquid, a passage in said body interconnecting said control and receiving chambers, a hollow valve stem fixed to the diaphragm and extending through said passage and through said receiving chamber, said interconnecting passage having an annular space surrounding the valve stem, an outlet channel in the body member extending from said annular space, seal ring members surrounding the hollow valve stem and positioned respectively adjacent the outer surface of the control chamber, at the inner end of the receiving chamber and at the outer end thereof, the hollow valve stem having lateral valve ports cooperating respectively with the control chamber seal ring and the seal ring at the inner end of the receiving chamber, and having a shoulder adjacent its inner end cooperating with the seal ring at the outer end of the receiving chamber, a valve opening in said partition between said outer and inner timing chambers, a spring closed valve cooperating with said opening, and the diaphragm actuating said valve member to open the same on the diaphragm outer stroke thus quickly equalizing the pressure in the two timing chambers and allowing the diaphragm to complete its outward stroke and then commence its return stroke.
 8. An automatic fluid discharging device for use with a pressure pack containing a pressurized fluid which comprises: a. a fluid timing system including first and second chambers interconnected by a constricted passage and by a pressure equalizing valve, the second chamber being filled with timing fluid, at least one wall of the second chamber being flexible for varying the enclosed volume, and means providing snap action of said flexible wall between outwardly and inwardly flexed positions thereof, means actuated by said flexible wall for operating said pressure equalizing valve, and b. A pressurized fluid section including, a metering and discharge chamber adjacent said flexible wall, a duct extending from the pressure pack to said metering and discharge chamber and to said flexible wall having an inlet valve therein, a valve stem actuated by said flexible wall, a discharge outlet and valve therefor, and means actuated by said stem for controlling said inlet and discharge valves. 